Chemoenzymatically prepared konjac ceramide inhibits NGF-induced neurite outgrowth by a semaphorin 3A-like action

Dietary sphingolipids such as glucosylceramide (GlcCer) are potential nutritional factors associated with prevention of metabolic syndrome. Our current understanding is that dietary GlcCer is degraded to ceramide and further metabolized to sphingoid bases in the intestine. However, ceramide is only found in trace amounts in food plants and thus is frequently taken as GlcCer in a health supplement. In the present study, we successfully prepared konjac ceramide (kCer) using endoglycoceramidase I (EGCase I). Konjac, a plant tuber, is an enriched source of GlcCer (kGlcCer), and has been commercialized as a dietary supplement to improve dry skin and itching that are caused by a deficiency of epidermal ceramide. Nerve growth factor (NGF) produced by skin cells is one of the itch factors in the stratum corneum of the skin. Semaphorin 3A (Sema 3A) has been known to inhibit NGF-induced neurite outgrowth of epidermal nerve fibers. It is well known that the itch sensation is regulated by the balance between NGF and Sema 3A. In the present study, while kGlcCer did not show an in vitro inhibitory effect on NGF-induced neurite outgrowth of PC12 cells, kCer was demonstrated to inhibit a remarkable neurite outgrowth. In addition, the effect of kCer was similar to that of Sema 3A in cell morphological changes and neurite retractions, but different from C2-Ceramide. kCer showed a Sema 3A-like action, causing CRMP2 phosphorylation, which results in a collapse of neurite growth cones. Thus, it is expected that kCer is an advanced konjac ceramide material that may have neurite outgrowth-specific action to relieve uncontrolled and serious itching, in particular, from atopic eczema.     

枯草芽孢杆菌产β-甘露聚糖酶固体发酵条件的优化

芽孢杆菌是产甘露聚糖酶的优良菌株,首次研究芽孢杆菌固体发酵条件的优化。以天然麸皮作为基本原料,研究利用枯草芽孢杆菌WY34固体发酵生产β-片露聚糖酶的发酵条件。最佳固体发酵培养条件为：麸皮5g,初始水分含量71％,初始pH7．0,接种量为2mL,1％Tween-80,0.4g魔芋粉,培养温度50℃。在最适条件下培养5d,甘露聚糖酶酶活高达7,650U／g干基,是未优化前酶活的2．78倍。     

Effect of γ-irradiation on some physiochemical properties of konjac glucomannan

Konjac glucomannan (KGM) was irradiated at 5, 20, 50 and 100 kGy and the effects of γ-irradiation on some physiochemical properties of KGM were studied by using viscosimeter, colorimeter, gel permeation chromatography (GPC), Fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV) spectroscopy, thermal gravimetric (TG) analysis and scanning electron microscopy (SEM). γ-irradiation led to significant degradation of KGM according to the significant reduction of the weight-average molecular weight (M_w). The apparent viscosity of KGM decreased with increasing dose, while the viscosity stability was improved after irradiation. The colour of KGM became more intense brown with increasing dose up to 20 kGy. FT-IR spectra indicated that γ-irradiation introduced no significant changes into the structure but UV spectra showed a distinct absorption peak at about 265 nm, increasing with irradiation dose, which was attributed to the formation of carbonyl groups or double bond. High irradiation dose (100 kGy) caused a small decrease of thermal stability but presented no visible fissures or splitting of KGM granules according to the TG analysis and SEM microphotographs.     

Konjac glucomannan hydrolysate: A potential natural coating material for bioactive compounds in spray drying encapsulation

This research aimed to develop a suitable coating material for encapsulating a plant bioactive compound via spray drying. A suitable process for modifying the rheological property of konjac glucomannan (KGM) solution by enzymatic treatment was developed. A plant bioactive compound, andrographolide, was selected to use as core material. Mannanase (1500 units of enzyme) was used in the treatment of KGM solution. The concentration of KGM solution was varied from 9 to 18% (w/w). It was found that 12% (w/w) was the optimum KGM concentration that could be hydrolyzed to a viscosity of <100 mPa·s. HPLC analysis of hydrolyzed solution found a fair amount of DP4–DP7 oligosaccharides (where DP is degree of polymerization) were obtained. The solution was then used as coating material in spray drying with inlet air temperature of 170°C and outlet air temperature of 85°C. It was found that 12% (w/w) konjac glucomannan hydrolysate (KGMH) was suitable for coating 2% (w/w) andrographolide. Its efficiency of encapsulation was also higher than that of KGMH combined with gamma‐cyclodextrin or beta‐cyclodextrin. This study revealed a great potential of using KGMH solution for pharmaceutical and food industries in the spray drying encapsulation process.